Recent studies have shown that a large portion of the American public prefers to eat in front of the TV set. While snack tables or the like have long been available for this activity, consumers have felt a need for more permanent and sturdy tables which, at the same time, will not get in the way of other activities in the same room at other times.
Changes in lifestyles over the years have made consumers more demanding of multiple functions from furniture. This has led to the popularity of sofa/recliners, "home theater" systems, etc. A cocktail table which can convert to an eating surface would be a useful and popular addition to the list. The top of such a table would have to lift up and out, so that it would be suspended over the legs of a person seated on a sofa or chair.
This same adjustable approach would be equally useful for cocktail tables in business waiting rooms or offices which could convert to work surfaces, or to sections of counter top in small kitchens which would lift up and out to facilitate use by cooks seated on stools.
Convertible tables are known to the art. However, the mechanisms for such furniture are typically complicated and expensive, and often are less than sturdy enough to want to trust. It is thus an object of the invention to provide a mechanism for dual-height tables which is simple to build and use, inexpensive, and sturdy.
Several companies have begun to sell occasional tables with movable tops recently (see "Movable Tops Lifting Sales of Occasional Tables", Furniture Today, May 10, 1993, pp.9 and 12). To the best of the inventor's knowledge, the mechanisms for the tables being currently sold are either of the swivel or pivot kind, or are basically on the same kind of scissor leg mechanism as is used in recliner footrests.
The following patents are considered relevant to the state of the art:
Merrimen, U.S. Pat. No. 1,689,445 shows an ironing board/table. The mechanism uses parallel links with a slotted lever used to raise and lower the surface and lock it into place. The table top slides out of the way to allow the ironing board to be raised.
Stephenson, U.S. Pat. No. 2,170,098 shows a desk with a raisable top. The top is supported on two links, one of which is bent in a dog-leg shape. Springs are used to bias the links into position. The links function in an over-the-top action, whereby when the top is fully raised, the legs are over the center of balance, which tends to hold the top open. However, there is nothing locking the top in this position, and pushing on the top in a rearward direction would push the links back over the top of rotation, leading to the collapse of the top.
Carlsson, U.S. Pat. No. 2,585,535 shows a table having a vertically adjustable top. The mechanism uses a leaf spring to raise the top and a set of props to hold it in raised position. The top does not extend outwardly as it raises, although sections of the top may be slid on rails to allow insertion of a leaf. In fact, sliding the top sections outward releases the top mechanism, allowing it to lower.
Keal, U.S. Pat. No. 2,727,799 shows a table with an adjustable top which pivots up and to the side, like that of the present invention. The parallel links supporting the top do not go over center, an inherently unstable arrangement, and require a locking bar to hold them in place.
Kiraly, U.S. Pat. No. 3,347,184 also shows a table with a section which lifts up and out (to form a lectern, in this case). Kiraly's support links are locked by a multiple-slotted locking bar which allows the lectern top to be locked in several positions. The design is not adapted to supporting any weight on the lectern top, and the multiple positions of the locking bar are, at best, centered on the links--all other positions have both links to the weak side of center (i.e. the locking bar is what keeps the lectern from collapsing, not the inherent stability of the configuration.
Powers, U.S. Pat. No. 4,109,588 shows a cocktail type table in which four non-parallel links are pivoted at the center of the base of the table, forming a pedestal when the top is raised and a key member is inserted.